|
|
August 6th, 2010
 Placing your loaded ammo up high, next to your rifle’s loading port, can help you shoot faster, without disturbing your position behind the rifle. Many top 600-yard shooters, such as Sam Hall and Mike Davis, have fabricated their own high-mount cartridge caddies to place 10 or more rounds right next to their loading ports. With such a set-up, and a bit of practice, ace benchresters can fire 10 rounds in as little as 30 seconds.
If you’re handy with tools, you can build your own cartridge caddy from a block of delrin or wood, and a flexible mounting arm. But it does take time, and you may end up going through two or three prototypes before you get it “just right”.
Now there’s a “store-bought” solution. Creedmoor Sports offers the new Eller Straight Line Speed Feed Cartridge Holder. The Eller caddy has a large base that will support it on the bench. The flexible black stalk allows you to set the height and angle of the ammo block to your choosing. You can arrange your ammo horizontally, vertically, or something in-between. This unit can benefit any bench competitor, and we’ve even see this type of unit adapted by F-classers for “Belly Benchrest”. The Eller Cartridge Holder costs $94.95 and comes in two sizes: Small (6mm to 6.5×284), and Large (6.5×284 to magnum). Order item #E1002SM from Creedmoor Sports.
Share the post "New Eller Speed Feed Ammo Caddy from Creedmoor Sports"
August 1st, 2010
 Many readers have asked, “Is there an ammo case that holds short BR, PPC and Grendel cases securely — one without a lot of extra clearance that allows fired brass to fall out of their slots if the box is tipped?” Yes, the J & J BR-100 Ammo Case fits BR, PPC, and Grendel cases just right. Many folks use the large green/red MTM 100-round ammo boxes for transporting 6BR and 6PPC ammo. The big MTM boxes work fine with loaded rounds, but not so great with fired cases. If you tip the MTM box on its side, the empties can spill out. That’s frustrating if you’ve meticulously sorted your cases. You won’t have this problem with the J & J 100-round BR-100 ammo case. It has tighter vertical clearance, so your empties won’t come out of their slots if the case tips over or is stacked upside down.
BR-100 cases are bargain-priced at just $4.88, and they come in Red, Blue, Smoke, or White colors. In addition to the BR-100 case, varminters who need to carry large numbers of loaded rounds should check out J & J’s 175-round Rifle Ammo Case (photo below). This foam-lined ammo transporter, item LR-175, costs $18.16 and is the largest-capacity ammo case we’ve found. For more info go to JandJProducts.Com.
Share the post "BR/PPC Ammo Carriers Hold Cartridges Securely"
June 29th, 2010
The U.S. Army has begun shipping its new, improved 5.56×45 cartridge, the M855A1 Enhanced Performance Round, to U.S. troops in Afghanistan. The Army will procure over 200 million rounds of the new M855A1 ammo in the next 12-15 months, and soldiers in Afghanistan will begin using M855A1 ammo in the summer of 2010. The new round replaces the current M855 cartridge used by U.S. troops since the early 1980s.
The military sought to replace current M855 ammo because M855 has not performed adequately in the Afghan theater. Specific complaints include: 1) inability to effectively penetrate vehicle windshields; 2) poor long-range performance; and 3) failure to fragment even in short-range anti-personnel use. The Army’s Picatinny Arsenal claims that the new M855A1 has improved hard target capability, more consistent performance at all distances, improved accuracy, reduced muzzle flash, and higher velocity. M855A1 ammo is tailored for use in M4 carbines but should also give enhanced performance in M16s and M249s.
 New Steel-Tip Bullet Design
The 62-grain bullet for the new M855A1 ammo is a completely new design. While it may appear to have a plastic “ballistic tip”, that’s deceiving. The new bullet created for M855A1 ammo has a bismuth-tin alloy core with a steel “stacked-cone” penetrating tip. The photo at right shows the version from last year; the final production version may be slightly different (e.g. the final version tip is a different color). Apparently the latest bullet design is a winner. During testing, M855A1 ammo performed better than current 7.62mm ball ammunition against certain types of targets. According to Lt. Col. Jeffrey K. Woods, the program’s product manager, the new M855A1 ammo is “the best general purpose 5.56mm round ever produced. A true general purpose round, the M855A1 exceeds the performance of the current M855 against the many different types of targets likely to be encountered in combat.” The chart below illustrates how M855A1 ammo performs on hard targets compared to M855.
Over One Million Rounds Fired in Army Tests
Prior to initial production, the new M855A1 round underwent vigorous testing. Official qualification of the round consisted of a series of side-by-side tests with the current M855. Overall, the Army fired more than one million rounds to ensure the new cartridge met all expectations. The new M855A1 round is the “most thoroughly tested small caliber round ever fielded” according to Lt. Col. Woods. The new M855A1 is sometimes called “Green Ammo” because it uses a lead-free projectile. Woods said the M855A1’s bullet design shows how “greening” a previously hazardous material can also provide extremely beneficial performance improvements.
Share the post "U.S. Army Issues New M855A1 Ammo to Troops in Afghanistan"
June 17th, 2010
Hand-loaders know how to assemble bullet, brass, powder and primer into a loaded cartridge. But have you ever wondered how brass cartridge cases are formed, or how bullets are made, starting with raw materials? Federal Ammunition (a division of ATK) has created an interesting video that shows how factory-loaded ammo is created, from start to finish. The video shows how cartridge brass is cupped, drawn, sized, annealed, then finished-formed. In addition, you can see how bullets are formed then inserted in cartridges with automated machinery. This is a fascinating video, worth watching.
Bullet-Making Process at the Sierra Bullets Plant
A second video, produced for the Discovery Channel’s How Stuff Works TV show, illustrates how bullets are made at the Sierra Bullets plant. Watch 80-lb billets of lead being drawn into wire to be used as bullet cores. Then see how copper jackets are formed, lubed, sized and combined with bullet cores to create the finished product — precision bullets for hunters and match shooters.
Thanks to German Salazar for finding these two videos.
Share the post "Videos Show How Loaded Cartridges and Bullets Are Crafted"
June 3rd, 2010
 At around 2:15 on the afternoon of June 2nd, there was a fire and explosion at the Nosler production plant in Bend, Oregon. Apparently the accident started in the ballistics tunnel testing area. Employees reported a flash, then smoke followed by a “massive explosion” which was felt many blocks away. One employee who saw a bright flash alertly activated a fire alarm which helped speed the evacuation process.
Nosler Plant Fire and Explosion VIDEO Report
Thankfully, all the roughly 100 Nosler employees were able to evacuate safely, and there were apparently no serious injuries. The fire and explosion did do significant damage to the 80,000 square foot Nosler building. When fire crews arrived, they found major damage to the southeast corner of the Nosler plant, with thick smoke still pouring out.
Damage could run into the millions of dollars. A number of city blocks were evacuated and cordoned off. Right now the cause of the fire and explosion remains unknown, but the Bend Fire Department, state police agencies, and the federal BATF are commencing investigations.
CLICK HERE for Nosler Fire Damage Photos | CLICK HERE for KTVZ.com (Bend, Oregon) News Report
Share the post "Fire and Explosion at Nosler Plant in Bend, Oregon"
May 29th, 2010
 Since it was first released in 1965, Cartridges of the World by Frank Barnes, has been considered the definitive print resource on firearm cartridges. The current 12th Edition, edited by Holt Bodinson, was released late last year. The 568-page 12th Edition now describes over 1500 cartridges (from 0.1 inch to 0.95 inch caliber). This edition has interesting new articles on cartridge design and performance. The book includes dimensions, illustrations, a short history, and sample loading data for over 1500 different cartridges, including virtually every significant cartridge introduced since the early 1870s, with separate chapters on rimfires, shotgun shells, sporting rifle cartridges from the United States and Canada, Britain, and Europe, plus handgun cartridges, military cartridges, and limited production “wildcat” and “proprietary” cartridges. You won’t find all the narrow-focus or obscure wildcats, but the book is still a useful resource, well worth owning. It’s a “must-have” item for any serious cartridge collector.
Frank C. Barnes (1918-1992) began collecting information on handgun cartridges at the early age of 12, thanks to his father, a police officer. Frank Barnes was an innovative cartridge designer, who invented the original 308 x 1.5″ Barnes, predecessor of the 30BR case. Before Frank began a law enforcement career, he was a college professor. Frank was also a pilot, and a race-car driver.
Cartridges of the World was first published in 1965. It’s lived through 12 editions and can be found on many reloaders’ bookshelves today. Suggested retail for the book is $32.99, but MidwayUSA currently sells the 12th Edition for $19.99 plus shipping (Midway item 242319). Amazon.com offers the book for $21.77 with free shipping on combined orders over $25.00.
AMAZON LINK: Cartridges of the World (12th Ed.): Complete Reference for Over 1500 Cartridges
Share the post "New 12th Edition of Cartridges of the World Available"
November 24th, 2009
 Hornady recently announced its new line of Superformance Hunting Ammo. Loaded with GMX solid bullets and SST jacketed bullets, the new ammo is faster than conventional hunting ammunition. Hornady claims that, “across the board”, Superformance ammo is 100-200 fps faster than other factory hunting ammo with similar bullet weights.
We had a lengthy discussion yesterday with Dave Emary, Hornady’s Senior Ballistician. Dave shared some of the secrets of the new Superperformance ammo, and explained how Hornady is achieving such high velocities. The key, as we suspected, is that Hornady is using new propellants — powders that are not yet available for sale. These new propellants are BALL POWDERS custom-made to Hornady’s specs. Hornady actually commissioned multiple new spherical formulations, in various speed ranges. Then Hornady blends these ball powders to suit particular cartridges and loads. So, each type of Superformance ammo (e.g. 243 Win with 95gr SST and 300 Win Mag with 165gr GMX) represents a custom blend of the new ball propellants of various burn ranges. Hornady tailors the powder blend to achieve maximum velocity, accuracy, and low temp sensitivity for each load.
Hornady is NOT using Alliant’s Reloder 17. However, in some respects, Hornady’s new ball powders behave like Reloder 17 — by “flattening the right side of the pressure curve”. Rather than hitting a high peak pressure and then dropping off dramatically in energy, Reloder 17 sustains high pressure behind the heel of the bullet for a longer in-barrel time. Hornady’s new powders do the same thing — they deliver high energy behind the bullet for more milliseconds as the bullet travels down the bore. This is the main reason Superformance ammo delivers high velocity — the new powders are maintaining higher energy levels for a longer period of time. Additionally, being ball powders that pack tightly, the new propellants can be loaded to a high density in the case — an advantage with medium-sized cartridges such as the 6.5 Creedmoor.
| Here is how Hornady has achieved high velocities with its new Superformance ammunition:
1) Superformance ammo uses advanced new Ball Powders (not yet for sale).
2) The powders are BLENDED, with different “recipes” for different cartridges.
3) The new powders maintain high-energy longer in barrel (like Reloder 17).
4) The new powders burn almost completely, reducing ejecta, for less exit pressure, and less felt recoil.
5) Superformance ball propellants pack very densely, so more grains of powder can fit inside a case, compared to typical extruded stick powders. |
 High Progressivity Powders
In addition to high sustained energy, Emary noted, the new propellants exhibit very high “progressivity”. What this means, in practical terms, is that the new propellants achieve almost 100% burn by the end of the cycle. So, virtually all of the mass of the powder has changed to gas by the time the bullet exits the muzzle. As a result, Emary explained “with Superformance propellants you have less ejecta leaving the muzzle. With some other extruded powders, you’ll get unburned or partly burned sticks leaving the muzzle”. Why does that matter? Dave explains there are a couple major benefits to high progressivity. First, you get “every last ounce of energy” out of each powder kernel. Second, because less unburned ejecta is driven out the barrel, the amount of recoil is reduced, particularly for the large magnum cases.
Dave explains: “In the past, small arms performance has been limited by the powder’s ability to completely burn by the time the bullet exits the muzzle. To attempt to get higher performance, high charge weights of a slow burning powder were used to attempt to maximize muzzle velocity. Powders were not progressive enough to allow these heavy charges of slow powder to be completely burned by the time the bullet left the muzzle, especially with lighter-weight bullets. The end result was very modest increases in velocity with heavy recoil and many times unacceptable accuracy. Superformance powders solve this problem because of their ability to completely burn by bullet muzzle exit…. This results in a much higher percentage of the available powder energy being transferred to the projectile, rather than being blown out the end of the barrel as unburned powder[.]”
In practical terms, Emary stated, the high energy and high progressivity of the new propellants permit many cartridges to deliver “real-world” performance equaling that of larger cartridges loaded with conventional powders. For example, according to Dave, “the 6.5 Creedmoor is performing on a par with a Rem .260.” Dave cited the example of his own 6.5 Creedmoor hunting rifle: “It shoots as flat as a .260 and the accuracy is as good or better.”
Dave has authored a detailed report that shows how 30-06 Superformance ammo can match the velocities of Hornady’s “light magnum” 30-06 ammo loaded with conventional powders. The Superformance 30-06 achieved similar velocities, with equivalent peak pressures, while using 6 grains less powder. This is illlustrated in the graph below.
Dave’s report states: “[The chart] shows a comparison of Chamber Pressure vs. Time for Custom, Superformance and Light Magnum ammunition in 30-06 loaded with a 150 gr SST bullet. As can be seen from the graph, all loads produced approximately the same pressure but have widely different charge weights and velocity performance. There is considerably more area under the curve for both Superformance and Light Magnum. This is where the increase in performance comes from. One detail to note is that the Superformance chamber pressure has dropped to at or below that of the Custom ammunition by the time the bullet exits the muzzle. This shows the highly progressive burning characteristics of the powder and its ability to completely burn. As noted above, the charge weights which go along with the different loads and the performance achieved with them are quite different. Custom is loaded with 58.5 grs of powder, Superformance 61.0 grs and Light Magnum 67.0 grs. Superformance ammunition produces significantly higher velocities than Custom with only a small amount more powder and the same velocity as Light Magnum with significantly less powder.”
Superformance Ammo for Match Shooters May Be Next
Right now Hornady is marketing its Superformance line as hunting ammunition only. However, Hornady recognizes that the new propellant technology could benefit match shooters as well. Dave told us that Hornady has begun development of a 6.5 Creedmoor Superformance round using the 140gr A-Max bullet.
Share the post "Hornady's Emary Shares Superformance Ammo Secrets"
November 23rd, 2009
We know that factory ammo for popular handgun calibers is still hard to find. This has lead to ammunition hording by handgun owners and painful price hikes from some ammo vendors. We saw one dealer charging nearly $40.00 for a 50-rd box of .380 ACP, more than double what the same ammo sold for 18 months ago. However, if you search around you’ll find that prices are starting to drop and we’re seeing supplies that haven’t been available in months.
Decent Pricing on 9mm and 40sw Can Be Found
Thankfully, some major dealers are holding the line on ammo prices and not taking advantage of the current supply shortages. Ammoman.com has Winchester 9mm ammo with 147gr BEB (Brass Enclosed Base) bullets at a good price: $159 for 500 rounds. This is new, US-made ammo ideal for use at indoor ranges as the enclosed base bullet design reduces lead pollution. With BEB bullets, guns run cleaner too as there is no vaporized lead left in the barrel.
For 40sw shooters, both Grafs.com and MidwayUSA.com have the PRVI Partisan 40sw 180gr TMJ ammo in stock right now. Graf’s sells the 40sw Prvi ammo for $20.99 per 50rd box, while MidwayUSA has the same product (40sw, 180gr TMJ) for $21.49 per 50rd box. Those are decent prices for factory ammo these days.
Share the post "Prices Start to "Normalize" for Handgun Ammo"
November 19th, 2009
Hornady Manufacturing has just announced its new line of “Superformance” hunting ammunition. Hornady claims that, “across the board” the new Superformance ammo will deliver “100 to 200 fps higher velocities than any other standard ammunition currently available.” Hornady also claims its Superformance ammo delivers increased velocities “WITHOUT increases in felt recoil, muzzle blast, temperature sensitivity, fouling or loss of accuracy.” Hornady President Steve Hornady says this is “a whole new standard in ammunition performance… We are going to be able to raise the velocity of almost any [hunting] load you’ve ever used… by 100-200 fps.” Surprisingly, the marketing materials even claim that Superformance ammo delivers higher velocities with “no increases in barrel wear” — something that runs contrary to common sense.
Rather amazing claims are being made for this new Hornady ammo. Are such claims to be believed? Well, when AccurateShooter.com tested Alliant Reloder 17 powder last year we confirmed that it could deliver 100-200 fps more velocity than most popular powders, in some cartridges. Presumably, Hornady is employing propellants with technologies similar to Reloder 17. Hornady’s marketing materials state that it is using “ultra progressive” “21st Century” propellants for the new Superformance ammo. Hornady has also brought out a line of GMX® mono-metal bullets that feature two deep cannelures for reduced bearing surface. It is well-established that this kind of bullet design can yield higher velocities, particularly in the big-bore calibers with heavy bullets.
 So… the velocity claims may be bonafied, though we would expect the velocity gains will vary among the cartridges. Some chamberings will benefit from the new propellants more than others. And only half the Superformance ammo line-up features GMX bullets, the other half being loaded with more conventional SST® bullets.
How about the claims regarding recoil? The claim that Superformance ammo can deliver 100-200 fps more velocity without any more recoil is questionable. Hornady can’t alter the laws of physics. If a bullet of given weight has a higher muzzle velocity, it MUST produce more recoil than the same bullet moving slower — provided that the propellant charge weight (and rifle weight) are held constant. The only way Hornady can achieve higher velocities without increased recoil is by either: 1) reducing bullet weight; or 2) reducing the powder charge (or gas-related recoil). Hornady could hold recoil constant if its new propellants achieve the higher velocities with a reduced powder charge compared to “conventional” loads.
Hornady has issued an 11-page technical report that provides support for many of its marketing claims. Authored by Hornady Senior Ballistician Dave Emary, the report features some interesting test results, summarized in graphs. Regarding the recoil question, Emary argues that “Recoil … has parts to it that are not commonly understood. The fundamental misunderstanding of recoil is that the recoil is over when the bullet leaves the barrel. In truth, the vast majority of recoil occurs after the projectile exits the barrel. By far the greatest percentage of recoil is produced by the force of the gases and propellant residue/ejecta leaving the barrel.” Emary cites test results showing that “approximately 85 – 90% of the recoil happens after the projectile has left the barrel”. If Emary is correct, then Hornady might be able to achieve higher bullet velocities without enhanced recoil, provided the gas-based force is reduced.
We strongly recommend you read Emary’s report. CLICK HERE to download Superformance Ammo Report.
Hornady plans to release a complete line-up of Superformance ammunition for twenty chamberings: 243 Win, 6mm Rem, 257 Roberts, 25-06, 6.5 Creedmoor, 270 win, 7×57, 7mm-08, 280 Rem, 7mm Mag, 308 Win, 30 TC, 30-06, 300 RCM, 300 Win Mag, 338 RCM, 338 Win Mag, 375 H&H, 375 Ruger, and 458 Win Mag. CLICK HERE to review all the available calibers and bullet options for Superformance ammunition.
Share the post "Hornady Announces NEW Superformance Ammunition — Claims 100-200 FPS More Velocity"
November 15th, 2009
 Since 2001, November 19th has been decreed National Ammo Day. The backers of this event want each and every gun owner to purchase 100 rounds of ammunition this Thursday the 19th. The purpose of Ammo Day is to support the Second Amendment and to send a message to politicians.
There are an estimated 75 MILLION gun owners in the United States. If even 10% of them purchase ammo on Nov. 19th, this will demonstrate the size, and economic importance, of the gun-owning citizenry. If there’s one thing politicians cannot ignore, it’s tax revenues. The sales and excise taxes on guns and ammo help support many important public programs.
To learn more about National Ammo Day, visit www.Ammoday.com. Unfortunately, certain types of ammunition remain in short supply. Because of the surge in gun and ammo sales following last year’s Presidential election, most ammunition is quite a bit more costly than it was 12 months ago… if you can find it at all. One person, commenting on the Ammoday.com website, expressed his frustration with price hikes: “How about we don’t purchase any ammo on the 19th to send a message to the manufacturers that the price gouging better stop, or we’ll simply reload everything we shoot.” He has a point. However, in a market economy, supply and demand will always influence price levels.
Share the post "National Ammo Day is November 19th"
September 29th, 2009
 We reported recently that the California Legislature passed AB 962. This bill would require anyone buying pistol ammo to provide drivers’ license #, address, and a thumbprint. And, because AB 962 requires all pistol ammo sales to be “face to face”, the law would effectively ban mail-order ammo sales in California. While AB 962 targets pistol ammo sales, it could also apply to any type of rifle ammo that has been used in pistols (including single-shots). That would include 22LR, 22 rimfire magnum, .223 Rem, 6BR, 30-30, .308 Winchester, and more.
Opposition Efforts Gain Strength
Right now, unless CA Governor Schwarzenegger vetoes AB 962 before October 11, 2009, the bill will become law, effective February 1, 2011. Californians need your help convincing Gov. Schwarzenegger to veto AB 962. The good news is that many sportsmen and shooters, both inside and outside California, have already contacted the Governor. But opponents of AB 962 need to do more. The NSSF reports:
“With great support from Cabela’s and major distributors throughout the country, grassroots efforts to combat three anti-gun bills in California have been so strong that the Governor’s Office has had to open up another fax line (916-445-4633) to handle demands that he veto the anti-gun legislation. NSSF is encouraging all manufacturers, retailers and distributors, along with all sportsmen, gun owners and firearms enthusiasts, to continue calling, writing and faxing Gov. Schwarzenegger’s office urging him to veto AB 962 (ammunition registration).”
AB 962 May Affect Ammo Prices Outside California
Why should non-Californians care about this legislation? First, remember that over 10% of the nation’s population resides in California. If the CA market is effectively closed off to major mail-order ammo vendors, their volume will decrease significantly, and that could result in price hikes in other markets. Second, this law sets a terrible precedent. If California can effectively require registration of all persons who purchase ammo, you know that full gun registration will be the next step.
Accordingly, we request that all our readers take a few seconds to communicate with Gov. Schwarzenegger and ask him to veto AB 962. This is easy to do. You can quickly voice your opinion by calling, e-mailing, or faxing the Governor (fax line is 916-445-4633).
 |
Telephone the Governor and Ask Him to Veto AB 962:
Step 1: Call 916-445-2841
Step 2: Press 1 for English
Step 3: Press 2 for commenting on a bill on the Governor’s desk
Step 4: Press 2 for AB 962
Step 5: Press 2 for Oppose |
|
 |
Email the Governor and Ask Him to Veto AB 962:
Step 1: Go to www.Gov.Ca.Gov/interact
Step 2: Fill in name and email address
Step 3: Select “GUN CONTROL” from pull-down menu
Step 4: Click “SUBMIT” (No, you’re not done yet!!)
A new page will open…
Step 5: Type in your message. It can be as simple as: “Please VETO AB 962. This bill will cost California in lost tax revenues. It also violates the rights of law-abiding citizens.”
Step 6: Click SEND |
Share the post "Gun Owners Nationwide Seek Veto of California AB 962"
April 5th, 2009
[This item last appeared a year ago in our Daily Bulletin, generating considerable interest among readers. By popular request, we’re reprinting this story, in case you missed it the first time around. — Editor]
Precision shooters favor premium brass from Lapua, Norma, or RWS. (Lake City also makes quality brass in military calibers.) Premium brass delivers better accuracy, more consistent velocities, and longer life. Shooters understand the importance of good brass, but many of us have no idea how cartridge cases are actually made. Here’s how it’s done.
The process starts with a brass disk stamped from strips of metal. Then, through a series of stages, the brass is extruded or drawn into a cylindrical shape. In the extrusion process the brass is squeezed through a die under tremendous pressure. This is repeated two or three times typically. In the more traditional “draw” process, the case is progressively stretched longer, in 3 to 5 stages, using a series of high-pressure rams forcing the brass into a form die. While extrusion may be more common today, RWS, which makes some of the most uniform brass in the world, still uses the draw process: “It starts with cup drawing after the bands have been punched out. RWS cases are drawn in three ‘stages’ and after each draw they are annealed, pickled, rinsed and subjected to further quality improvement measures. This achieves specific hardening of the brass cases and increases their resistance to extraordinary stresses.” FYI, Lapua also uses a traditional draw process to manufacture most of its cartridge brass (although Lapua employs some proprietary steps that are different from RWS’ methods).
After the cases are extruded or drawn to max length, the cases are trimmed and the neck/shoulder are formed. Then the extractor groove (on rimless cases) is formed or machined, and the primer pocket is created in the base. One way to form the primer pocket is to use a hardened steel plug called a “bunter”. In the photos below you see the stages for forming a 20mm cannon case (courtesy OldAmmo.com), along with bunters used for Lake City rifle brass. This illustrates the draw process (as opposed to extrusion). The process of draw-forming rifle brass is that same as for this 20mm shell, just on a smaller scale.
River Valley Ordnance explains: “When a case is being made, it is drawn to its final draw length, with the diameter being slightly smaller than needed. At this point in its life, the head of the draw is slightly rounded, and there are no provisions for a primer. So the final drawn cases are trimmed to length, then run into the head bunter. A punch, ground to the intended contours for the inside of the case, pushes the draw into a cylindrical die and holds it in place while another punch rams into the case from the other end, mashing the bottom flat. That secondary ram holds the headstamp bunter punch.
The headstamp bunter punch has a protrusion on the end to make the primer pocket, and has raised lettering around the face to form the headstamp writing. This is, of course, all a mirror image of the finished case head. Small cases, such as 5.56×45, can be headed with a single strike. Larger cases, like 7.62×51 and 50 BMG, need to be struck once to form a dent for the primer pocket, then a second strike to finish the pocket, flatten the head, and imprint the writing. This second strike works the brass to harden it so it will support the pressure of firing.”
Thanks to Guy Hildebrand, of the Cartridge Collectors’ Exchange, OldAmmo.com, for providing this 20mm Draw Set photo. Bunter photo from River Valley Ordnance, RVOW.com.
Share the post "How Cartridge Brass is Made"
|
